54 Below presents Sondheimas, "the annual quasi-religious celebration of the birth of the savior of musical theater, Stephen Sondheim." The one-night-only concert will be performed March 21, on the eve of the legendary composer's 85th birthday.

Sondheimas returns to the midtown cabaret following a sold-out show last year. It is billed as a "raucous celebration of the man, the music, and the mythos" that features songs both familiar and unknown.

The show is produced by David Levy and Maggie Larkin, with musical direction by Andrei Strizek. It was inspired by author Rachel Shukert, who first described the holiday on twitter and then further expanded on it in her book "Let Me Be Your Star."